Core won't boot anymore, dead STM32F4?

[Nirokesan]

I finished my build today, turned on my SeqV4… some LEDs lit up, and there are solid top rows (black bar) on the LCD displays.   There is a red LED flashing on the STM32F4.  What’s going on?

 

I built my core and tested the discovery board months ago with LCDs attached.  Successfully set up, read SD card, screens displayed as expected.  I haven’t turned on the core since then as I’ve been focused on enclosures and other aspects of the build.   

Now today, I assemble the enclosure with my CS board, two MIDI I/O, one Quad IIc, and one Line Tx.   I removed the USB Power jumper and connected this 5V DC/DC converter that was recommended to me by another SeqV4 builder https://www.adafruit.com/product/1385   The AC adapter I used was 7.5V/2A.   When I turned it on, I got the results described at the top of this post.  I powered off, disassembled, and tested the output of the converter which measured 5.27V.    Next, I replaced the USB Power jumper, disconnected all peripherals except the LCDs, and powered up using the USB port.  Same result, core won’t boot.  

Could the 5.27V supply have damaged the discovery board?  Do these symptoms sound indicative of some other failure or user error?

Thanks so much for any help!   

 

 

 

 

 

[EvilEvilEvil]

Same exact thing I’m experiencing. It worked and I put it aside for some weeks while I built the other mods. Now it doesn’t and just produces the black bars on the LCD. I’ve rebuilt my core, ordered another LCD and tried another discovery board - same result. It makes no sense because it worked fine several weeks ago. TK, please help! 

http://discourse.midibox.org/t/topic/20095

What does MIOS Studio say? Does Seq4 actually start?

[Nirokesan]

Evil, thanks for your response!  Strange, I never noticed your post, didn’t make the connection.  I will read through the replies there soon.  Glad to hear that was not solved by replacing the discovery board or core, as that would add some wait time while I ordered a new one, but at the same time this news is rather unfortunate.  Did you also add modules/peripherals between when it worked and failed?  Are you using external power?  Perhaps this is covered in your thread.

I haven’t loaded up MIOS Studio yet, I only connected to the computer for USB power.  Will try that and report back within 24 hrs 

[Nirokesan]

Seems ok via MIOS Studio, as far as I can tell at least

 

[T.K]

For me it’s very interesting, that we now have a second case with similar symptoms. Maybe this gives me the missing hint for the root cause.

Questions to you:

• did you ever connect the LCD cable the wrong way by accident?
  Please don’t try to change the cable orientation - this could destroy the LCD.
  If you are able to change the contrast of the black bars with the contrast pot, you know that it’s currently connected the right way
• which LCD are you using exactly?
• does the same happen if only a single LCD is connected?
• could you please check the connections with the “testlcdpin” command and report the measurements?
• I built different STM32F4 core modules in the past, some of them are frequently used - and I never noticed such a problem.
  But there might be a general difference in my configuration: in the bootloader, I enabled “fastboot” mode.
  Could you please try the same at your side? The setup procedure is documented here: http://www.ucapps.de/mios32_bootstrap_newbies.html

Best Regards, Thorsten. 

[Nirokesan]

TK, 

Thank you for your reply!  

I can only answer your first question right now because I have to leave for work…but my LCDs have only been connected two or three times, and each time the same way as far as I can recall.  The red stripe on my ribbon is at the arrow on the keyed connector at the Core, and at Pin 1 on my LCDs. 

PLEASE NOTE: I think this is not how the connection is shown in Evil’s thread!  That connection shows red stripe at Pin 1 of Core but at PIN 16 of LCD!  

Turning the contrast pot has no obvious effect, but turning the LUMI pot makes the bars nearly invisible. 

I will investigate your other points when I return home for lunch in 4.5hrs

Thank you!

[EvilEvilEvil]

Mine is hooked up with the red stripe on the arrow to the Core and to pin 15 on the LCD, like so: http://ucapps.de/mbhp/mbhp_lcd_2x20_mios32.pdf

Contrast and brightness work for me.

So that could be your issue - although you say it worked fine before?

[T.K]

I updated the documentation at the bottom of this page http://www.ucapps.de/mbhp_core_stm32f4.html

It shows how the LCD should be connected

And I’ve some good news: I tried the wrong connection with one of my old LCDs - and this didn’t fry the LCD.
Instead, the Lumi pot changed the contrast - exactly the same effect noticed by

Changing the connection again - LCD working again!

So, I think that my statement, that a wrong connection destroys the LCD is wrong, I just never tried this.
Actually this was based on experiences with the PIC based MBHP_CORE module, which had a different pinning.
For 32bit cores a new pinning has been introduced, which seems to be fool-proven.
And also based on the circuit this makes sense (although it wasn’t my intention): Vs/Vd will be connected to B-/B+ if the connector is rotated, so that the Lumination pot controls the LCD supply current instead of the backlight supply.

Best Regards, Thorsten.

[Nirokesan]

Yes, I just looked at a few other pics of working LCD connections and see that they are opposite to mine.  It’s possible that when I connected my LCDs to run bootloader and MIOS, I went by the datasheet…and when I later assembled my enclosure, I went 1:1. So does that mean these LCDs are cooked?  Need to order new?  I will attempt to find info on my LCDs, ordered from eBay  

I will still run “testlcdpin” when I get home (if I can figure out how)

[Nirokesan]

Great news, TK!  Thank you for your efforts!  I will fix my connections when I get home and see if things work again.  This however does not explain why Evil is still having a problem with new LCDs and correct connections…

[EvilEvilEvil]

Hey TK - thanks!

Can you also indicate where the square outlined pin is on the LCD (I assume that the square one is Pin1?) According to your picture I don’t have mine arranged correctly however the red stripe IS going to pin 15 on my LCD

[T.K]

The square is at the same side like the notch, and it shows to pin number 2 (because the connector is mounted at the bottom of the LCD, and not at the top)

This can be very confusing, therefore I prefer pictures

Best Regards, Thorsten.

[Nirokesan]

TK, 

 Thanks so much, I’m back in business!  Lumi pot dims the screens to black, but contrast doesn’t do anything at all no matter the Lumi setting.

 

[T.K]

Great!

I can only speculate about the contrast pot - as you can see in the schematic: http://www.ucapps.de/mbhp/mbhp_core_stm32f4.pdf it sets the V0 voltage between Vs and Vd (0..5V) - do you measure this voltage change?

Best Regards, Thorsten.

[Nirokesan]

I may have spoken too soon… yes, my displays are working, but my CS is not.  More on that in a moment.  

As for the contrast pot: I just tested the voltage at the V0 pin on J15A, and it sweeps from 0V to 4.89V.  So I’m not sure what’s wrong with that feature.  But this reminds me to ask, am I ok to power the system using that 5.27V supply?

When I tested earlier today and sent that celebratory image above, the only connections to the Core were those of the LCDs.   Since arriving home from work, and after testing the contrast voltage, I plugged in the other modules to try and test/verify that they work. (I’m not sure how to do this using MIOS Studio or where to find a list of suitable commands for the modules I’m using.)  My MIDI_IO boards all lit up momentarily upon powering, but after that first time, each time I turned it on I would notice that some LEDs did not flash.  The Quad_IIc also flashed, but it occurred at a slight delay if compared to the MIDI_IO.  I’ll assume these are probably OK until I can verify.

However the CS seems to be confused.  When I connect to the Core and power up, the LEDs at “track group 4”, “trigger layer 3”, “parameter layer 3”, “fast”, and “all” are all illuminated, and no others.  Pressing buttons does not seem to do what it should, multiple buttons perform the same function, and some buttons do nothing.  

For example, multiple buttons caused this display:

multiple others caused this display (edit recording was flashing over other text):

Pressing C/3/Manual caused this display:

Pressing Pattern:

Pressing Fast:

 

and there were more…

Is this another case of a reversed ribbon??  I thought I had been so careful throughout this build! 

Below is the entirety of the .txt file on my SD card which should be the recommended Wilba-compatible configuration with no modifications…yet.

 

 

MBSEQ_HW.V4.txt

 

 

[T.K]

This is exactly the behavior if there is no (or no matching) MBSEQ_HW.V4 file on your SD Card.
Because in this case the “standard frontpanel” layout will be selected, which has no multiplexers (like Wilba’s one) - hence, one button can trigger multiple functions, and some LEDs are assigned to 8 functions as well.

Note that the file is named “MBSEQ_HW.V4” and not “MBSEQ_HW.V4.txt” - could this be the error?

Are you aware of this page which describes the installation procedure?
http://www.ucapps.de/midibox_seq_manual_in.html

The MBSEQ_HW.V4 file is located in the hwcfg/wilba directory of the release package.

The latest firmware version can be found under: http://www.ucapps.de/mios32_download.html
We’ve V4.094 meanwhile… and the MBSEQ_HW.V4 has changed…

Best Regards, Thorsten. 

[Nirokesan]

TK, 

  Thank you again!  Yes, that installation page is what I referred to when setting up my discovery board, I’m not sure how I managed to add the file extension on to the configuration file.  I replaced the .txt on my card with the latest V4.094 and now everything seems to work as it should. 

However, before I reassemble the enclosure, I need to confirm that my external power is suitable.  Can I use that 5.27VDC supply?  Or do I need to get it below 5V (like the 4.89V from my USB port)?

Enjoy a couple of beers with my appreciation, but do let us know what you’re having!

[T.K]

I’m not sure if the higher voltage is good for all components; if you want to be at the save side, don’t use it!

Best Regards, Thorsten.